Resolve index names in indices_boost

This change allows specifying alias/wildcard expression in indices_boost.
And added another format for specifying indices_boost. It accepts array of index name and boost pair.
If an index is included in multiple aliases/wildcard expressions, the first match will be used.
With new format, old format is marked as deprecated.

Closes #4756

core/src/main/java/org/elasticsearch/action/search/AbstractSearchAsyncAction.java

@@ -50,6 +50,7 @@ import java.util.function.Function;
 
 
 abstract class AbstractSearchAsyncAction<FirstResult extends SearchPhaseResult> extends AbstractAsyncAction {
+    private static final float DEFAULT_INDEX_BOOST = 1.0f;
 
     protected final Logger logger;
     protected final SearchTransportService searchTransportService;
@@ -66,6 +67,7 @@ abstract class AbstractSearchAsyncAction<FirstResult extends SearchPhaseResult>
     private final AtomicInteger totalOps = new AtomicInteger();
     protected final AtomicArray<FirstResult> firstResults;
     private final Map<String, AliasFilter> aliasFilter;
+    private final Map<String, Float> concreteIndexBoosts;
     private final long clusterStateVersion;
     private volatile AtomicArray<ShardSearchFailure> shardFailures;
     private final Object shardFailuresMutex = new Object();
@@ -73,9 +75,9 @@ abstract class AbstractSearchAsyncAction<FirstResult extends SearchPhaseResult>
 
     protected AbstractSearchAsyncAction(Logger logger, SearchTransportService searchTransportService,
                                         Function<String, DiscoveryNode> nodeIdToDiscoveryNode,
-                                        Map<String, AliasFilter> aliasFilter, Executor executor, SearchRequest request,
+                                        Map<String, AliasFilter> aliasFilter, Map<String, Float> concreteIndexBoosts,
-                                        ActionListener<SearchResponse> listener, GroupShardsIterator shardsIts, long startTime,
+                                        Executor executor, SearchRequest request, ActionListener<SearchResponse> listener,
-                                        long clusterStateVersion, SearchTask task) {
+                                        GroupShardsIterator shardsIts, long startTime, long clusterStateVersion, SearchTask task) {
         super(startTime);
         this.logger = logger;
         this.searchTransportService = searchTransportService;
@@ -91,6 +93,7 @@ abstract class AbstractSearchAsyncAction<FirstResult extends SearchPhaseResult>
         expectedTotalOps = shardsIts.totalSizeWith1ForEmpty();
         firstResults = new AtomicArray<>(shardsIts.size());
         this.aliasFilter = aliasFilter;
+        this.concreteIndexBoosts = concreteIndexBoosts;
     }
 
     public void start() {
@@ -125,8 +128,10 @@ abstract class AbstractSearchAsyncAction<FirstResult extends SearchPhaseResult>
             } else {
                 AliasFilter filter = this.aliasFilter.get(shard.index().getUUID());
                 assert filter != null;
+
+                float indexBoost = concreteIndexBoosts.getOrDefault(shard.index().getUUID(), DEFAULT_INDEX_BOOST);
                 ShardSearchTransportRequest transportRequest = new ShardSearchTransportRequest(request, shardIt.shardId(), shardsIts.size(),
-                    filter, startTime());
+                    filter, indexBoost, startTime());
                 sendExecuteFirstPhase(node, transportRequest , new ActionListener<FirstResult>() {
                         @Override
                         public void onResponse(FirstResult result) {

core/src/main/java/org/elasticsearch/action/search/SearchDfsQueryAndFetchAsyncAction.java

@@ -47,10 +47,11 @@ class SearchDfsQueryAndFetchAsyncAction extends AbstractSearchAsyncAction<DfsSea
     private final SearchPhaseController searchPhaseController;
     SearchDfsQueryAndFetchAsyncAction(Logger logger, SearchTransportService searchTransportService,
                                       Function<String, DiscoveryNode> nodeIdToDiscoveryNode,
-                                      Map<String, AliasFilter> aliasFilter, SearchPhaseController searchPhaseController,
+                                      Map<String, AliasFilter> aliasFilter, Map<String, Float> concreteIndexBoosts,
-                                      Executor executor, SearchRequest request, ActionListener<SearchResponse> listener,
+                                      SearchPhaseController searchPhaseController, Executor executor, SearchRequest request,
-                                      GroupShardsIterator shardsIts, long startTime, long clusterStateVersion, SearchTask task) {
+                                      ActionListener<SearchResponse> listener,  GroupShardsIterator shardsIts,
-        super(logger, searchTransportService, nodeIdToDiscoveryNode, aliasFilter, executor,
+                                      long startTime, long clusterStateVersion, SearchTask task) {
+        super(logger, searchTransportService, nodeIdToDiscoveryNode, aliasFilter, concreteIndexBoosts, executor,
                 request, listener, shardsIts, startTime, clusterStateVersion, task);
         this.searchPhaseController = searchPhaseController;
         queryFetchResults = new AtomicArray<>(firstResults.length());

core/src/main/java/org/elasticsearch/action/search/SearchDfsQueryThenFetchAsyncAction.java

@@ -55,11 +55,11 @@ class SearchDfsQueryThenFetchAsyncAction extends AbstractSearchAsyncAction<DfsSe
 
     SearchDfsQueryThenFetchAsyncAction(Logger logger, SearchTransportService searchTransportService,
                                        Function<String, DiscoveryNode> nodeIdToDiscoveryNode,
-                                       Map<String, AliasFilter> aliasFilter, SearchPhaseController searchPhaseController,
+                                       Map<String, AliasFilter> aliasFilter, Map<String, Float> concreteIndexBoosts,
-                                       Executor executor, SearchRequest request, ActionListener<SearchResponse> listener,
+                                       SearchPhaseController searchPhaseController, Executor executor, SearchRequest request,
-                                       GroupShardsIterator shardsIts, long startTime, long clusterStateVersion,
+                                       ActionListener<SearchResponse> listener, GroupShardsIterator shardsIts, long startTime,
-                                       SearchTask task) {
+                                       long clusterStateVersion, SearchTask task) {
-        super(logger, searchTransportService, nodeIdToDiscoveryNode, aliasFilter, executor,
+        super(logger, searchTransportService, nodeIdToDiscoveryNode, aliasFilter, concreteIndexBoosts, executor,
                 request, listener, shardsIts, startTime, clusterStateVersion, task);
         this.searchPhaseController = searchPhaseController;
         queryResults = new AtomicArray<>(firstResults.length());

core/src/main/java/org/elasticsearch/action/search/SearchQueryAndFetchAsyncAction.java

@@ -40,12 +40,12 @@ class SearchQueryAndFetchAsyncAction extends AbstractSearchAsyncAction<QueryFetc
 
     SearchQueryAndFetchAsyncAction(Logger logger, SearchTransportService searchTransportService,
                                    Function<String, DiscoveryNode> nodeIdToDiscoveryNode,
-                                   Map<String, AliasFilter> aliasFilter,
+                                   Map<String, AliasFilter> aliasFilter, Map<String, Float> concreteIndexBoosts,
                                    SearchPhaseController searchPhaseController, Executor executor,
                                    SearchRequest request, ActionListener<SearchResponse> listener,
                                    GroupShardsIterator shardsIts, long startTime, long clusterStateVersion,
                                    SearchTask task) {
-        super(logger, searchTransportService, nodeIdToDiscoveryNode, aliasFilter, executor,
+        super(logger, searchTransportService, nodeIdToDiscoveryNode, aliasFilter, concreteIndexBoosts, executor,
                 request, listener, shardsIts, startTime, clusterStateVersion, task);
         this.searchPhaseController = searchPhaseController;
 

core/src/main/java/org/elasticsearch/action/search/SearchQueryThenFetchAsyncAction.java

@@ -50,13 +50,13 @@ class SearchQueryThenFetchAsyncAction extends AbstractSearchAsyncAction<QuerySea
     private final SearchPhaseController searchPhaseController;
 
     SearchQueryThenFetchAsyncAction(Logger logger, SearchTransportService searchTransportService,
-                                    Function<String, DiscoveryNode> nodeIdToDiscoveryNode, Map<String,
+                                    Function<String, DiscoveryNode> nodeIdToDiscoveryNode,
-        AliasFilter> aliasFilter,
+                                    Map<String, AliasFilter> aliasFilter, Map<String, Float> concreteIndexBoosts,
                                     SearchPhaseController searchPhaseController, Executor executor,
                                     SearchRequest request, ActionListener<SearchResponse> listener,
                                     GroupShardsIterator shardsIts, long startTime, long clusterStateVersion,
                                     SearchTask task) {
-        super(logger, searchTransportService, nodeIdToDiscoveryNode, aliasFilter, executor, request, listener,
+        super(logger, searchTransportService, nodeIdToDiscoveryNode, aliasFilter, concreteIndexBoosts, executor, request, listener,
             shardsIts, startTime, clusterStateVersion, task);
         this.searchPhaseController = searchPhaseController;
         fetchResults = new AtomicArray<>(firstResults.length());

core/src/main/java/org/elasticsearch/action/search/TransportSearchAction.java

@@ -34,6 +34,7 @@ import org.elasticsearch.common.settings.Setting.Property;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.search.SearchService;
+import org.elasticsearch.search.builder.SearchSourceBuilder;
 import org.elasticsearch.search.internal.AliasFilter;
 import org.elasticsearch.tasks.Task;
 import org.elasticsearch.threadpool.ThreadPool;
@@ -84,6 +85,29 @@ public class TransportSearchAction extends HandledTransportAction<SearchRequest,
         return aliasFilterMap;
     }
 
+    private Map<String, Float> resolveIndexBoosts(SearchRequest searchRequest, ClusterState clusterState) {
+        if (searchRequest.source() == null) {
+            return Collections.emptyMap();
+        }
+
+        SearchSourceBuilder source = searchRequest.source();
+        if (source.indexBoosts() == null) {
+            return Collections.emptyMap();
+        }
+
+        Map<String, Float> concreteIndexBoosts = new HashMap<>();
+        for (SearchSourceBuilder.IndexBoost ib : source.indexBoosts()) {
+            Index[] concreteIndices =
+                indexNameExpressionResolver.concreteIndices(clusterState, searchRequest.indicesOptions(), ib.getIndex());
+
+            for (Index concreteIndex : concreteIndices) {
+                concreteIndexBoosts.putIfAbsent(concreteIndex.getUUID(), ib.getBoost());
+            }
+        }
+
+        return Collections.unmodifiableMap(concreteIndexBoosts);
+    }
+
     @Override
     protected void doExecute(Task task, SearchRequest searchRequest, ActionListener<SearchResponse> listener) {
         // pure paranoia if time goes backwards we are at least positive
@@ -107,6 +131,8 @@ public class TransportSearchAction extends HandledTransportAction<SearchRequest,
             searchRequest.preference());
         failIfOverShardCountLimit(clusterService, shardIterators.size());
 
+        Map<String, Float> concreteIndexBoosts = resolveIndexBoosts(searchRequest, clusterState);
+
         // optimize search type for cases where there is only one shard group to search on
         if (shardIterators.size() == 1) {
             // if we only have one group, then we always want Q_A_F, no need for DFS, and no need to do THEN since we hit one shard
@@ -125,7 +151,7 @@ public class TransportSearchAction extends HandledTransportAction<SearchRequest,
         }
 
         searchAsyncAction((SearchTask)task, searchRequest, shardIterators, startTimeInMillis, clusterState,
-            Collections.unmodifiableMap(aliasFilter), listener).start();
+            Collections.unmodifiableMap(aliasFilter), concreteIndexBoosts, listener).start();
     }
 
     @Override
@@ -135,6 +161,7 @@ public class TransportSearchAction extends HandledTransportAction<SearchRequest,
 
     private AbstractSearchAsyncAction searchAsyncAction(SearchTask task, SearchRequest searchRequest, GroupShardsIterator shardIterators,
                                                         long startTime, ClusterState state,  Map<String, AliasFilter> aliasFilter,
+                                                        Map<String, Float> concreteIndexBoosts,
                                                         ActionListener<SearchResponse> listener) {
         final Function<String, DiscoveryNode> nodesLookup = state.nodes()::get;
         final long clusterStateVersion = state.version();
@@ -143,22 +170,22 @@ public class TransportSearchAction extends HandledTransportAction<SearchRequest,
         switch(searchRequest.searchType()) {
             case DFS_QUERY_THEN_FETCH:
                 searchAsyncAction = new SearchDfsQueryThenFetchAsyncAction(logger, searchTransportService, nodesLookup,
-                    aliasFilter, searchPhaseController, executor, searchRequest, listener, shardIterators, startTime,
+                    aliasFilter, concreteIndexBoosts, searchPhaseController, executor, searchRequest, listener, shardIterators, startTime,
                     clusterStateVersion, task);
                 break;
             case QUERY_THEN_FETCH:
                 searchAsyncAction = new SearchQueryThenFetchAsyncAction(logger, searchTransportService, nodesLookup,
-                    aliasFilter, searchPhaseController, executor, searchRequest, listener, shardIterators, startTime,
+                    aliasFilter, concreteIndexBoosts, searchPhaseController, executor, searchRequest, listener, shardIterators, startTime,
                     clusterStateVersion, task);
                 break;
             case DFS_QUERY_AND_FETCH:
                 searchAsyncAction = new SearchDfsQueryAndFetchAsyncAction(logger, searchTransportService, nodesLookup,
-                    aliasFilter, searchPhaseController, executor, searchRequest, listener, shardIterators, startTime,
+                    aliasFilter, concreteIndexBoosts, searchPhaseController, executor, searchRequest, listener, shardIterators, startTime,
                     clusterStateVersion, task);
                 break;
             case QUERY_AND_FETCH:
                 searchAsyncAction = new SearchQueryAndFetchAsyncAction(logger, searchTransportService, nodesLookup,
-                    aliasFilter, searchPhaseController, executor, searchRequest, listener, shardIterators, startTime,
+                    aliasFilter, concreteIndexBoosts, searchPhaseController, executor, searchRequest, listener, shardIterators, startTime,
                     clusterStateVersion, task);
                 break;
             default:
@@ -177,5 +204,4 @@ public class TransportSearchAction extends HandledTransportAction<SearchRequest,
                 + "] to a greater value if you really want to query that many shards at the same time.");
         }
     }
-
 }

core/src/main/java/org/elasticsearch/search/DefaultSearchContext.java

@@ -96,7 +96,7 @@ final class DefaultSearchContext extends SearchContext {
     private final DfsSearchResult dfsResult;
     private final QuerySearchResult queryResult;
     private final FetchSearchResult fetchResult;
-    private float queryBoost = 1.0f;
+    private final float queryBoost;
     private TimeValue timeout;
     // terminate after count
     private int terminateAfter = DEFAULT_TERMINATE_AFTER;
@@ -173,6 +173,7 @@ final class DefaultSearchContext extends SearchContext {
         this.timeout = timeout;
         queryShardContext = indexService.newQueryShardContext(request.shardId().id(), searcher.getIndexReader(), request::nowInMillis);
         queryShardContext.setTypes(request.types());
+        queryBoost = request.indexBoost();
     }
 
     @Override
@@ -352,12 +353,6 @@ final class DefaultSearchContext extends SearchContext {
         return queryBoost;
     }
 
-    @Override
-    public SearchContext queryBoost(float queryBoost) {
-        this.queryBoost = queryBoost;
-        return this;
-    }
-
     @Override
     public long getOriginNanoTime() {
         return originNanoTime;

core/src/main/java/org/elasticsearch/search/SearchService.java

@@ -19,7 +19,6 @@
 
 package org.elasticsearch.search;
 
-import com.carrotsearch.hppc.ObjectFloatHashMap;
 import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.util.IOUtils;
@@ -679,13 +678,6 @@ public class SearchService extends AbstractLifecycleComponent implements IndexEv
         QueryShardContext queryShardContext = context.getQueryShardContext();
         context.from(source.from());
         context.size(source.size());
-        ObjectFloatHashMap<String> indexBoostMap = source.indexBoost();
-        if (indexBoostMap != null) {
-            Float indexBoost = indexBoostMap.get(context.shardTarget().index());
-            if (indexBoost != null) {
-                context.queryBoost(indexBoost);
-            }
-        }
         Map<String, InnerHitBuilder> innerHitBuilders = new HashMap<>();
         if (source.query() != null) {
             InnerHitBuilder.extractInnerHits(source.query(), innerHitBuilders);

core/src/main/java/org/elasticsearch/search/builder/SearchSourceBuilder.java

@@ -19,16 +19,16 @@
 
 package org.elasticsearch.search.builder;
 
-import com.carrotsearch.hppc.ObjectFloatHashMap;
 import org.elasticsearch.action.support.ToXContentToBytes;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.ParsingException;
 import org.elasticsearch.common.Strings;
-import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.common.logging.DeprecationLogger;
+import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
@@ -63,10 +63,6 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
-import java.util.stream.Collectors;
-import java.util.stream.StreamSupport;
-
-import static org.elasticsearch.common.collect.Tuple.tuple;
 
 /**
  * A search source builder allowing to easily build search source. Simple
@@ -76,6 +72,8 @@ import static org.elasticsearch.common.collect.Tuple.tuple;
  * @see org.elasticsearch.action.search.SearchRequest#source(SearchSourceBuilder)
  */
 public final class SearchSourceBuilder extends ToXContentToBytes implements Writeable {
+    private static final DeprecationLogger DEPRECATION_LOGGER =
+        new DeprecationLogger(Loggers.getLogger(SearchSourceBuilder.class));
 
     public static final ParseField FROM_FIELD = new ParseField("from");
     public static final ParseField SIZE_FIELD = new ParseField("size");
@@ -167,7 +165,7 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
 
     private List<RescoreBuilder> rescoreBuilders;
 
-    private ObjectFloatHashMap<String> indexBoost = null;
+    private List<IndexBoost> indexBoosts = new ArrayList<>();
 
     private List<String> stats;
 
@@ -193,13 +191,7 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
         storedFieldsContext = in.readOptionalWriteable(StoredFieldsContext::new);
         from = in.readVInt();
         highlightBuilder = in.readOptionalWriteable(HighlightBuilder::new);
-        int indexBoostSize = in.readVInt();
+        indexBoosts = in.readList(IndexBoost::new);
-        if (indexBoostSize > 0) {
-            indexBoost = new ObjectFloatHashMap<>(indexBoostSize);
-            for (int i = 0; i < indexBoostSize; i++) {
-                indexBoost.put(in.readString(), in.readFloat());
-            }
-        }
         minScore = in.readOptionalFloat();
         postQueryBuilder = in.readOptionalNamedWriteable(QueryBuilder.class);
         queryBuilder = in.readOptionalNamedWriteable(QueryBuilder.class);
@@ -240,11 +232,7 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
         out.writeOptionalWriteable(storedFieldsContext);
         out.writeVInt(from);
         out.writeOptionalWriteable(highlightBuilder);
-        int indexBoostSize = indexBoost == null ? 0 : indexBoost.size();
+        out.writeList(indexBoosts);
-        out.writeVInt(indexBoostSize);
-        if (indexBoostSize > 0) {
-            writeIndexBoost(out);
-        }
         out.writeOptionalFloat(minScore);
         out.writeOptionalNamedWriteable(postQueryBuilder);
         out.writeOptionalNamedWriteable(queryBuilder);
@@ -283,17 +271,6 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
         out.writeOptionalWriteable(sliceBuilder);
     }
 
-    private void writeIndexBoost(StreamOutput out) throws IOException {
-        List<Tuple<String, Float>> ibs = StreamSupport
-            .stream(indexBoost.spliterator(), false)
-            .map(i -> tuple(i.key, i.value)).sorted((o1, o2) -> o1.v1().compareTo(o2.v1()))
-            .collect(Collectors.toList());
-        for (Tuple<String, Float> ib : ibs) {
-            out.writeString(ib.v1());
-            out.writeFloat(ib.v2());
-        }
-    }
-
     /**
      * Sets the search query for this request.
      *
@@ -816,28 +793,26 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
     }
 
     /**
-     * Sets the boost a specific index will receive when the query is executed
+     * Sets the boost a specific index or alias will receive when the query is executed
      * against it.
      *
      * @param index
-     *            The index to apply the boost against
+     *            The index or alias to apply the boost against
      * @param indexBoost
      *            The boost to apply to the index
      */
     public SearchSourceBuilder indexBoost(String index, float indexBoost) {
-        if (this.indexBoost == null) {
+        Objects.requireNonNull(index, "index must not be null");
-            this.indexBoost = new ObjectFloatHashMap<>();
+        this.indexBoosts.add(new IndexBoost(index, indexBoost));
-        }
-        this.indexBoost.put(index, indexBoost);
         return this;
     }
 
     /**
-     * Gets the boost a specific indices will receive when the query is
+     * Gets the boost a specific indices or aliases will receive when the query is
      * executed against them.
      */
-    public ObjectFloatHashMap<String> indexBoost() {
+    public List<IndexBoost> indexBoosts() {
-        return indexBoost;
+        return indexBoosts;
     }
 
     /**
@@ -916,7 +891,7 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
         rewrittenBuilder.storedFieldsContext = storedFieldsContext;
         rewrittenBuilder.from = from;
         rewrittenBuilder.highlightBuilder = highlightBuilder;
-        rewrittenBuilder.indexBoost = indexBoost;
+        rewrittenBuilder.indexBoosts = indexBoosts;
         rewrittenBuilder.minScore = minScore;
         rewrittenBuilder.postQueryBuilder = postQueryBuilder;
         rewrittenBuilder.profile = profile;
@@ -1002,12 +977,13 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
                         scriptFields.add(new ScriptField(context));
                     }
                 } else if (context.getParseFieldMatcher().match(currentFieldName, INDICES_BOOST_FIELD)) {
-                    indexBoost = new ObjectFloatHashMap<>();
+                    DEPRECATION_LOGGER.deprecated(
+                        "Object format in indices_boost is deprecated, please use array format instead");
                     while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
                         if (token == XContentParser.Token.FIELD_NAME) {
                             currentFieldName = parser.currentName();
                         } else if (token.isValue()) {
-                            indexBoost.put(currentFieldName, parser.floatValue());
+                            indexBoosts.add(new IndexBoost(currentFieldName, parser.floatValue()));
                         } else {
                             throw new ParsingException(parser.getTokenLocation(), "Unknown key for a " + token +
                                 " in [" + currentFieldName + "].", parser.getTokenLocation());
@@ -1062,6 +1038,10 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
                                 "] in [" + currentFieldName + "] but found [" + token + "]", parser.getTokenLocation());
                         }
                     }
+                } else if (context.getParseFieldMatcher().match(currentFieldName, INDICES_BOOST_FIELD)) {
+                    while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
+                        indexBoosts.add(new IndexBoost(context));
+                    }
                 } else if (context.getParseFieldMatcher().match(currentFieldName, SORT_FIELD)) {
                     sorts = new ArrayList<>(SortBuilder.fromXContent(context));
                 } else if (context.getParseFieldMatcher().match(currentFieldName, RESCORE_FIELD)) {
@@ -1191,18 +1171,13 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
             builder.field(SLICE.getPreferredName(), sliceBuilder);
         }
 
-        if (indexBoost != null) {
+        builder.startArray(INDICES_BOOST_FIELD.getPreferredName());
-            builder.startObject(INDICES_BOOST_FIELD.getPreferredName());
+        for (IndexBoost ib : indexBoosts) {
-            assert !indexBoost.containsKey(null);
+            builder.startObject();
-            final Object[] keys = indexBoost.keys;
+            builder.field(ib.index, ib.boost);
-            final float[] values = indexBoost.values;
-            for (int i = 0; i < keys.length; i++) {
-                if (keys[i] != null) {
-                    builder.field((String) keys[i], values[i]);
-                }
-            }
             builder.endObject();
         }
+        builder.endArray();
 
         if (aggregations != null) {
             builder.field(AGGREGATIONS_FIELD.getPreferredName(), aggregations);
@@ -1237,6 +1212,91 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
         }
     }
 
+    public static class IndexBoost implements Writeable, ToXContent {
+        private final String index;
+        private final float boost;
+
+        IndexBoost(String index, float boost) {
+            this.index = index;
+            this.boost = boost;
+        }
+
+        IndexBoost(StreamInput in) throws IOException {
+            index = in.readString();
+            boost = in.readFloat();
+        }
+
+        IndexBoost(QueryParseContext context) throws IOException {
+            XContentParser parser = context.parser();
+            XContentParser.Token token = parser.currentToken();
+
+            if (token == XContentParser.Token.START_OBJECT) {
+                token = parser.nextToken();
+                if (token == XContentParser.Token.FIELD_NAME) {
+                    index = parser.currentName();
+                } else {
+                    throw new ParsingException(parser.getTokenLocation(), "Expected [" + XContentParser.Token.FIELD_NAME +
+                        "] in [" + INDICES_BOOST_FIELD + "] but found [" + token + "]", parser.getTokenLocation());
+                }
+                token = parser.nextToken();
+                if (token == XContentParser.Token.VALUE_NUMBER) {
+                    boost = parser.floatValue();
+                } else {
+                    throw new ParsingException(parser.getTokenLocation(), "Expected [" + XContentParser.Token.VALUE_NUMBER +
+                        "] in [" + INDICES_BOOST_FIELD + "] but found [" + token + "]", parser.getTokenLocation());
+                }
+                token = parser.nextToken();
+                if (token != XContentParser.Token.END_OBJECT) {
+                    throw new ParsingException(parser.getTokenLocation(), "Expected [" + XContentParser.Token.END_OBJECT +
+                        "] in [" + INDICES_BOOST_FIELD + "] but found [" + token + "]", parser.getTokenLocation());
+                }
+            } else {
+                throw new ParsingException(parser.getTokenLocation(), "Expected [" + XContentParser.Token.START_OBJECT +
+                    "] in [" + parser.currentName() + "] but found [" + token + "]", parser.getTokenLocation());
+            }
+        }
+
+        public String getIndex() {
+            return index;
+        }
+
+        public float getBoost() {
+            return boost;
+        }
+
+        @Override
+        public void writeTo(StreamOutput out) throws IOException {
+            out.writeString(index);
+            out.writeFloat(boost);
+        }
+
+        @Override
+        public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+            builder.startObject();
+            builder.field(index, boost);
+            builder.endObject();
+            return builder;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(index, boost);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj == null) {
+                return false;
+            }
+            if (getClass() != obj.getClass()) {
+                return false;
+            }
+            IndexBoost other = (IndexBoost) obj;
+            return Objects.equals(index, other.index)
+                && Objects.equals(boost, other.boost);
+        }
+
+    }
     public static class ScriptField implements Writeable, ToXContent {
 
         private final boolean ignoreFailure;
@@ -1352,8 +1412,9 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
     @Override
     public int hashCode() {
         return Objects.hash(aggregations, explain, fetchSourceContext, docValueFields, storedFieldsContext, from, highlightBuilder,
-                indexBoost, minScore, postQueryBuilder, queryBuilder, rescoreBuilders, scriptFields, size, sorts, searchAfterBuilder,
+                indexBoosts, minScore, postQueryBuilder, queryBuilder, rescoreBuilders, scriptFields, size,
-                sliceBuilder, stats, suggestBuilder, terminateAfter, timeout, trackScores, version, profile, extBuilders);
+                sorts, searchAfterBuilder, sliceBuilder, stats, suggestBuilder, terminateAfter, timeout, trackScores, version,
+                profile, extBuilders);
     }
 
     @Override
@@ -1372,7 +1433,7 @@ public final class SearchSourceBuilder extends ToXContentToBytes implements Writ
                 && Objects.equals(storedFieldsContext, other.storedFieldsContext)
                 && Objects.equals(from, other.from)
                 && Objects.equals(highlightBuilder, other.highlightBuilder)
-                && Objects.equals(indexBoost, other.indexBoost)
+                && Objects.equals(indexBoosts, other.indexBoosts)
                 && Objects.equals(minScore, other.minScore)
                 && Objects.equals(postQueryBuilder, other.postQueryBuilder)
                 && Objects.equals(queryBuilder, other.queryBuilder)

core/src/main/java/org/elasticsearch/search/internal/FilteredSearchContext.java

@@ -37,7 +37,6 @@ import org.elasticsearch.index.query.ParsedQuery;
 import org.elasticsearch.index.query.QueryShardContext;
 import org.elasticsearch.index.shard.IndexShard;
 import org.elasticsearch.index.similarity.SimilarityService;
-import org.elasticsearch.script.ScriptService;
 import org.elasticsearch.search.SearchExtBuilder;
 import org.elasticsearch.search.SearchShardTarget;
 import org.elasticsearch.search.aggregations.SearchContextAggregations;
@@ -144,11 +143,6 @@ public abstract class FilteredSearchContext extends SearchContext {
         return in.queryBoost();
     }
 
-    @Override
-    public SearchContext queryBoost(float queryBoost) {
-        return in.queryBoost(queryBoost);
-    }
-
     @Override
     public long getOriginNanoTime() {
         return in.getOriginNanoTime();

core/src/main/java/org/elasticsearch/search/internal/SearchContext.java

@@ -148,8 +148,6 @@ public abstract class SearchContext extends AbstractRefCounted implements Releas
 
     public abstract float queryBoost();
 
-    public abstract SearchContext queryBoost(float queryBoost);
-
     public abstract long getOriginNanoTime();
 
     public abstract ScrollContext scrollContext();

core/src/main/java/org/elasticsearch/search/internal/ShardSearchLocalRequest.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.search.internal;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.action.search.SearchRequest;
 import org.elasticsearch.action.search.SearchType;
 import org.elasticsearch.common.Strings;
@@ -34,6 +35,7 @@ import org.elasticsearch.search.Scroll;
 import org.elasticsearch.search.builder.SearchSourceBuilder;
 
 import java.io.IOException;
+import java.util.Optional;
 
 /**
  * Shard level search request that gets created and consumed on the local node.
@@ -63,6 +65,7 @@ public class ShardSearchLocalRequest implements ShardSearchRequest {
     private Scroll scroll;
     private String[] types = Strings.EMPTY_ARRAY;
     private AliasFilter aliasFilter;
+    private float indexBoost;
     private SearchSourceBuilder source;
     private Boolean requestCache;
     private long nowInMillis;
@@ -73,9 +76,9 @@ public class ShardSearchLocalRequest implements ShardSearchRequest {
     }
 
     ShardSearchLocalRequest(SearchRequest searchRequest, ShardId shardId, int numberOfShards,
-                            AliasFilter aliasFilter, long nowInMillis) {
+                            AliasFilter aliasFilter, float indexBoost, long nowInMillis) {
         this(shardId, numberOfShards, searchRequest.searchType(),
-                searchRequest.source(), searchRequest.types(), searchRequest.requestCache(), aliasFilter);
+                searchRequest.source(), searchRequest.types(), searchRequest.requestCache(), aliasFilter, indexBoost);
         this.scroll = searchRequest.scroll();
         this.nowInMillis = nowInMillis;
     }
@@ -85,10 +88,11 @@ public class ShardSearchLocalRequest implements ShardSearchRequest {
         this.nowInMillis = nowInMillis;
         this.aliasFilter = aliasFilter;
         this.shardId = shardId;
+        indexBoost = 1.0f;
     }
 
     public ShardSearchLocalRequest(ShardId shardId, int numberOfShards, SearchType searchType, SearchSourceBuilder source, String[] types,
-            Boolean requestCache, AliasFilter aliasFilter) {
+            Boolean requestCache, AliasFilter aliasFilter, float indexBoost) {
         this.shardId = shardId;
         this.numberOfShards = numberOfShards;
         this.searchType = searchType;
@@ -96,6 +100,7 @@ public class ShardSearchLocalRequest implements ShardSearchRequest {
         this.types = types;
         this.requestCache = requestCache;
         this.aliasFilter = aliasFilter;
+        this.indexBoost = indexBoost;
     }
 
 
@@ -134,6 +139,11 @@ public class ShardSearchLocalRequest implements ShardSearchRequest {
         return aliasFilter.getQueryBuilder();
     }
 
+    @Override
+    public float indexBoost() {
+        return indexBoost;
+    }
+
     @Override
     public long nowInMillis() {
         return nowInMillis;
@@ -167,6 +177,20 @@ public class ShardSearchLocalRequest implements ShardSearchRequest {
         source = in.readOptionalWriteable(SearchSourceBuilder::new);
         types = in.readStringArray();
         aliasFilter = new AliasFilter(in);
+        if (in.getVersion().onOrAfter(Version.V_5_2_0_UNRELEASED)) {
+            indexBoost = in.readFloat();
+        } else {
+            // Nodes < 5.2.0 doesn't send index boost. Read it from source.
+            if (source != null) {
+                Optional<SearchSourceBuilder.IndexBoost> boost = source.indexBoosts()
+                    .stream()
+                    .filter(ib -> ib.getIndex().equals(shardId.getIndexName()))
+                    .findFirst();
+                indexBoost = boost.isPresent() ? boost.get().getBoost() : 1.0f;
+            } else {
+                indexBoost = 1.0f;
+            }
+        }
         nowInMillis = in.readVLong();
         requestCache = in.readOptionalBoolean();
     }
@@ -181,6 +205,9 @@ public class ShardSearchLocalRequest implements ShardSearchRequest {
         out.writeOptionalWriteable(source);
         out.writeStringArray(types);
         aliasFilter.writeTo(out);
+        if (out.getVersion().onOrAfter(Version.V_5_2_0_UNRELEASED)) {
+            out.writeFloat(indexBoost);
+        }
         if (!asKey) {
             out.writeVLong(nowInMillis);
         }

core/src/main/java/org/elasticsearch/search/internal/ShardSearchRequest.java

@@ -62,6 +62,8 @@ public interface ShardSearchRequest {
 
     QueryBuilder filteringAliases();
 
+    float indexBoost();
+
     long nowInMillis();
 
     Boolean requestCache();

core/src/main/java/org/elasticsearch/search/internal/ShardSearchTransportRequest.java

@@ -54,8 +54,8 @@ public class ShardSearchTransportRequest extends TransportRequest implements Sha
     }
 
     public ShardSearchTransportRequest(SearchRequest searchRequest, ShardId shardId, int numberOfShards,
-                                       AliasFilter aliasFilter, long nowInMillis) {
+                                       AliasFilter aliasFilter, float indexBoost, long nowInMillis) {
-        this.shardSearchLocalRequest = new ShardSearchLocalRequest(searchRequest, shardId, numberOfShards, aliasFilter, nowInMillis);
+        this.shardSearchLocalRequest = new ShardSearchLocalRequest(searchRequest, shardId, numberOfShards, aliasFilter, indexBoost, nowInMillis);
         this.originalIndices = new OriginalIndices(searchRequest);
     }
 
@@ -111,6 +111,11 @@ public class ShardSearchTransportRequest extends TransportRequest implements Sha
         return shardSearchLocalRequest.filteringAliases();
     }
 
+    @Override
+    public float indexBoost() {
+        return shardSearchLocalRequest.indexBoost();
+    }
+
     @Override
     public long nowInMillis() {
         return shardSearchLocalRequest.nowInMillis();

core/src/main/java/org/elasticsearch/search/internal/SubSearchContext.java

@@ -22,14 +22,13 @@ import org.apache.lucene.search.Query;
 import org.apache.lucene.util.Counter;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.index.query.ParsedQuery;
-import org.elasticsearch.search.fetch.StoredFieldsContext;
 import org.elasticsearch.search.aggregations.SearchContextAggregations;
 import org.elasticsearch.search.fetch.FetchSearchResult;
+import org.elasticsearch.search.fetch.StoredFieldsContext;
 import org.elasticsearch.search.fetch.subphase.DocValueFieldsContext;
 import org.elasticsearch.search.fetch.subphase.FetchSourceContext;
 import org.elasticsearch.search.fetch.subphase.ScriptFieldsContext;
 import org.elasticsearch.search.fetch.subphase.highlight.SearchContextHighlight;
-import org.elasticsearch.search.lookup.SearchLookup;
 import org.elasticsearch.search.query.QuerySearchResult;
 import org.elasticsearch.search.rescore.RescoreSearchContext;
 import org.elasticsearch.search.sort.SortAndFormats;
@@ -85,11 +84,6 @@ public class SubSearchContext extends FilteredSearchContext {
         throw new UnsupportedOperationException("this context should be read only");
     }
 
-    @Override
-    public SearchContext queryBoost(float queryBoost) {
-        throw new UnsupportedOperationException("Not supported");
-    }
-
     @Override
     public SearchContext scrollContext(ScrollContext scrollContext) {
         throw new UnsupportedOperationException("Not supported");

core/src/test/java/org/elasticsearch/action/search/SearchAsyncActionTests.java

@@ -88,7 +88,7 @@ public class SearchAsyncActionTests extends ESTestCase {
         lookup.put(primaryNode.getId(), primaryNode);
         Map<String, AliasFilter> aliasFilters = Collections.singletonMap("_na_", new AliasFilter(null, Strings.EMPTY_ARRAY));
         AbstractSearchAsyncAction asyncAction = new AbstractSearchAsyncAction<TestSearchPhaseResult>(logger, transportService, lookup::get,
-            aliasFilters, null, request, responseListener, shardsIter, 0, 0, null) {
+            aliasFilters, Collections.emptyMap(), null, request, responseListener, shardsIter, 0, 0, null) {
             TestSearchResponse response = new TestSearchResponse();
 
             @Override

core/src/test/java/org/elasticsearch/index/SearchSlowLogTests.java

@@ -87,6 +87,11 @@ public class SearchSlowLogTests extends ESSingleNodeTestCase {
                     return null;
                 }
 
+                @Override
+                public float indexBoost() {
+                    return 1.0f;
+                }
+
                 @Override
                 public long nowInMillis() {
                     return 0;

core/src/test/java/org/elasticsearch/search/SearchServiceTests.java

@@ -185,7 +185,7 @@ public class SearchServiceTests extends ESSingleNodeTestCase {
                 try {
                     QuerySearchResultProvider querySearchResultProvider = service.executeQueryPhase(
                         new ShardSearchLocalRequest(indexShard.shardId(), 1, SearchType.DEFAULT,
-                            new SearchSourceBuilder(), new String[0], false, new AliasFilter(null, Strings.EMPTY_ARRAY)),
+                            new SearchSourceBuilder(), new String[0], false, new AliasFilter(null, Strings.EMPTY_ARRAY), 1.0f),
                         new SearchTask(123L, "", "", "", null));
                     IntArrayList intCursors = new IntArrayList(1);
                     intCursors.add(0);
@@ -220,7 +220,8 @@ public class SearchServiceTests extends ESSingleNodeTestCase {
                 new SearchSourceBuilder(),
                 new String[0],
                 false,
-                new AliasFilter(null, Strings.EMPTY_ARRAY)),
+                new AliasFilter(null, Strings.EMPTY_ARRAY),
+                1.0f),
             null);
         // the search context should inherit the default timeout
         assertThat(contextWithDefaultTimeout.timeout(), equalTo(TimeValue.timeValueSeconds(5)));
@@ -234,7 +235,8 @@ public class SearchServiceTests extends ESSingleNodeTestCase {
                 new SearchSourceBuilder().timeout(TimeValue.timeValueSeconds(seconds)),
                 new String[0],
                 false,
-                new AliasFilter(null, Strings.EMPTY_ARRAY)),
+                new AliasFilter(null, Strings.EMPTY_ARRAY),
+                1.0f),
             null);
         // the search context should inherit the query timeout
         assertThat(context.timeout(), equalTo(TimeValue.timeValueSeconds(seconds)));

core/src/test/java/org/elasticsearch/search/builder/SearchSourceBuilderTests.java

@@ -301,4 +301,78 @@ public class SearchSourceBuilderTests extends AbstractSearchTestCase {
         String query = "{ \"query\": {} }";
         assertParseSearchSource(builder, new BytesArray(query), ParseFieldMatcher.EMPTY);
     }
+
+    public void testParseIndicesBoost() throws IOException {
+        {
+            String restContent = " { \"indices_boost\": {\"foo\": 1.0, \"bar\": 2.0}}";
+            try (XContentParser parser = XContentFactory.xContent(restContent).createParser(restContent)) {
+                SearchSourceBuilder searchSourceBuilder = SearchSourceBuilder.fromXContent(createParseContext(parser),
+                    searchRequestParsers.aggParsers, searchRequestParsers.suggesters, searchRequestParsers.searchExtParsers);
+                assertEquals(2, searchSourceBuilder.indexBoosts().size());
+                assertEquals(new SearchSourceBuilder.IndexBoost("foo", 1.0f), searchSourceBuilder.indexBoosts().get(0));
+                assertEquals(new SearchSourceBuilder.IndexBoost("bar", 2.0f), searchSourceBuilder.indexBoosts().get(1));
+            }
+        }
+
+        {
+            String restContent = "{" +
+                "    \"indices_boost\" : [\n" +
+                "        { \"foo\" : 1.0 },\n" +
+                "        { \"bar\" : 2.0 },\n" +
+                "        { \"baz\" : 3.0 }\n" +
+                "    ]}";
+            try (XContentParser parser = XContentFactory.xContent(restContent).createParser(restContent)) {
+                SearchSourceBuilder searchSourceBuilder = SearchSourceBuilder.fromXContent(createParseContext(parser),
+                    searchRequestParsers.aggParsers, searchRequestParsers.suggesters, searchRequestParsers.searchExtParsers);
+                assertEquals(3, searchSourceBuilder.indexBoosts().size());
+                assertEquals(new SearchSourceBuilder.IndexBoost("foo", 1.0f), searchSourceBuilder.indexBoosts().get(0));
+                assertEquals(new SearchSourceBuilder.IndexBoost("bar", 2.0f), searchSourceBuilder.indexBoosts().get(1));
+                assertEquals(new SearchSourceBuilder.IndexBoost("baz", 3.0f), searchSourceBuilder.indexBoosts().get(2));
+            }
+        }
+
+        {
+            String restContent = "{" +
+                "    \"indices_boost\" : [\n" +
+                "        { \"foo\" : 1.0, \"bar\": 2.0}\n" + // invalid format
+                "    ]}";
+
+            assertIndicesBoostParseErrorMessage(restContent, "Expected [END_OBJECT] in [indices_boost] but found [FIELD_NAME]");
+        }
+
+        {
+            String restContent = "{" +
+                "    \"indices_boost\" : [\n" +
+                "        {}\n" + // invalid format
+                "    ]}";
+
+            assertIndicesBoostParseErrorMessage(restContent, "Expected [FIELD_NAME] in [indices_boost] but found [END_OBJECT]");
+        }
+
+        {
+            String restContent = "{" +
+                "    \"indices_boost\" : [\n" +
+                "        { \"foo\" : \"bar\"}\n" + // invalid format
+                "    ]}";
+
+            assertIndicesBoostParseErrorMessage(restContent, "Expected [VALUE_NUMBER] in [indices_boost] but found [VALUE_STRING]");
+        }
+
+        {
+            String restContent = "{" +
+                "    \"indices_boost\" : [\n" +
+                "        { \"foo\" : {\"bar\": 1}}\n" + // invalid format
+                "    ]}";
+
+            assertIndicesBoostParseErrorMessage(restContent, "Expected [VALUE_NUMBER] in [indices_boost] but found [START_OBJECT]");
+        }
+    }
+
+    private void assertIndicesBoostParseErrorMessage(String restContent, String expectedErrorMessage) throws IOException {
+        try (XContentParser parser = XContentFactory.xContent(restContent).createParser(restContent)) {
+            ParsingException e = expectThrows(ParsingException.class, () -> SearchSourceBuilder.fromXContent(createParseContext(parser),
+                searchRequestParsers.aggParsers, searchRequestParsers.suggesters, searchRequestParsers.searchExtParsers));
+            assertEquals(expectedErrorMessage, e.getMessage());
+        }
+    }
 }

core/src/test/java/org/elasticsearch/search/indicesboost/SimpleIndicesBoostSearchIT.java

@@ -1,107 +0,0 @@
-/*
- * Licensed to Elasticsearch under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-package org.elasticsearch.search.indicesboost;
-
-import org.elasticsearch.action.search.SearchResponse;
-import org.elasticsearch.action.search.SearchType;
-import org.elasticsearch.test.ESIntegTestCase;
-
-import static org.elasticsearch.client.Requests.indexRequest;
-import static org.elasticsearch.client.Requests.searchRequest;
-import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
-import static org.elasticsearch.index.query.QueryBuilders.termQuery;
-import static org.elasticsearch.search.builder.SearchSourceBuilder.searchSource;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertHitCount;
-import static org.hamcrest.Matchers.equalTo;
-
-public class SimpleIndicesBoostSearchIT extends ESIntegTestCase {
-    public void testIndicesBoost() throws Exception {
-        assertHitCount(client().prepareSearch().setQuery(termQuery("test", "value")).get(), 0);
-
-        try {
-            client().prepareSearch("test").setQuery(termQuery("test", "value")).execute().actionGet();
-            fail("should fail");
-        } catch (Exception e) {
-            // ignore, no indices
-        }
-
-        createIndex("test1", "test2");
-        ensureGreen();
-        client().index(indexRequest("test1").type("type1").id("1")
-                .source(jsonBuilder().startObject().field("test", "value check").endObject())).actionGet();
-        client().index(indexRequest("test2").type("type1").id("1")
-                .source(jsonBuilder().startObject().field("test", "value beck").endObject())).actionGet();
-        refresh();
-
-        float indexBoost = 1.1f;
-
-        logger.info("--- QUERY_THEN_FETCH");
-
-        logger.info("Query with test1 boosted");
-        SearchResponse response = client().search(searchRequest()
-                .searchType(SearchType.QUERY_THEN_FETCH)
-                .source(searchSource().explain(true).indexBoost("test1", indexBoost).query(termQuery("test", "value")))
-        ).actionGet();
-
-        assertThat(response.getHits().totalHits(), equalTo(2L));
-        logger.info("Hit[0] {} Explanation {}", response.getHits().getAt(0).index(), response.getHits().getAt(0).explanation());
-        logger.info("Hit[1] {} Explanation {}", response.getHits().getAt(1).index(), response.getHits().getAt(1).explanation());
-        assertThat(response.getHits().getAt(0).index(), equalTo("test1"));
-        assertThat(response.getHits().getAt(1).index(), equalTo("test2"));
-
-        logger.info("Query with test2 boosted");
-        response = client().search(searchRequest()
-                .searchType(SearchType.QUERY_THEN_FETCH)
-                .source(searchSource().explain(true).indexBoost("test2", indexBoost).query(termQuery("test", "value")))
-        ).actionGet();
-
-        assertThat(response.getHits().totalHits(), equalTo(2L));
-        logger.info("Hit[0] {} Explanation {}", response.getHits().getAt(0).index(), response.getHits().getAt(0).explanation());
-        logger.info("Hit[1] {} Explanation {}", response.getHits().getAt(1).index(), response.getHits().getAt(1).explanation());
-        assertThat(response.getHits().getAt(0).index(), equalTo("test2"));
-        assertThat(response.getHits().getAt(1).index(), equalTo("test1"));
-
-        logger.info("--- DFS_QUERY_THEN_FETCH");
-
-        logger.info("Query with test1 boosted");
-        response = client().search(searchRequest()
-                .searchType(SearchType.DFS_QUERY_THEN_FETCH)
-                .source(searchSource().explain(true).indexBoost("test1", indexBoost).query(termQuery("test", "value")))
-        ).actionGet();
-
-        assertThat(response.getHits().totalHits(), equalTo(2L));
-        logger.info("Hit[0] {} Explanation {}", response.getHits().getAt(0).index(), response.getHits().getAt(0).explanation());
-        logger.info("Hit[1] {} Explanation {}", response.getHits().getAt(1).index(), response.getHits().getAt(1).explanation());
-        assertThat(response.getHits().getAt(0).index(), equalTo("test1"));
-        assertThat(response.getHits().getAt(1).index(), equalTo("test2"));
-
-        logger.info("Query with test2 boosted");
-        response = client().search(searchRequest()
-                .searchType(SearchType.DFS_QUERY_THEN_FETCH)
-                .source(searchSource().explain(true).indexBoost("test2", indexBoost).query(termQuery("test", "value")))
-        ).actionGet();
-
-        assertThat(response.getHits().totalHits(), equalTo(2L));
-        logger.info("Hit[0] {} Explanation {}", response.getHits().getAt(0).index(), response.getHits().getAt(0).explanation());
-        logger.info("Hit[1] {} Explanation {}", response.getHits().getAt(1).index(), response.getHits().getAt(1).explanation());
-        assertThat(response.getHits().getAt(0).index(), equalTo("test2"));
-        assertThat(response.getHits().getAt(1).index(), equalTo("test1"));
-    }
-}

core/src/test/java/org/elasticsearch/search/internal/ShardSearchTransportRequestTests.java

@@ -81,6 +81,7 @@ public class ShardSearchTransportRequestTests extends AbstractSearchTestCase {
                 assertEquals(deserializedRequest.cacheKey(), shardSearchTransportRequest.cacheKey());
                 assertNotSame(deserializedRequest, shardSearchTransportRequest);
                 assertEquals(deserializedRequest.filteringAliases(), shardSearchTransportRequest.filteringAliases());
+                assertEquals(deserializedRequest.indexBoost(), shardSearchTransportRequest.indexBoost(), 0.0f);
             }
         }
     }
@@ -96,7 +97,7 @@ public class ShardSearchTransportRequestTests extends AbstractSearchTestCase {
             filteringAliases = new AliasFilter(null, Strings.EMPTY_ARRAY);
         }
         return new ShardSearchTransportRequest(searchRequest, shardId,
-                randomIntBetween(1, 100), filteringAliases, Math.abs(randomLong()));
+                randomIntBetween(1, 100), filteringAliases, randomBoolean() ? 1.0f : randomFloat(), Math.abs(randomLong()));
     }
 
     public void testFilteringAliases() throws Exception {
@@ -213,4 +214,24 @@ public class ShardSearchTransportRequestTests extends AbstractSearchTestCase {
         }
     }
 
+    // BWC test for changes from #21393
+    public void testSerialize50RequestForIndexBoost() throws IOException {
+        BytesArray requestBytes = new BytesArray(Base64.getDecoder()
+            // this is a base64 encoded request generated with the same input
+            .decode("AAZpbmRleDEWTjEyM2trbHFUT21XZDY1Z2VDYlo5ZwABBAABAAIA/wD/////DwABBmluZGV4MUAAAAAAAAAAAP////8PAAAAAAAAAgAAAA" +
+                "AAAPa/q8mOKwIAJg=="));
+
+        try (StreamInput in = new NamedWriteableAwareStreamInput(requestBytes.streamInput(), namedWriteableRegistry)) {
+            in.setVersion(Version.V_5_0_0);
+            ShardSearchTransportRequest readRequest = new ShardSearchTransportRequest();
+            readRequest.readFrom(in);
+            assertEquals(0, in.available());
+            assertEquals(2.0f, readRequest.indexBoost(), 0);
+
+            BytesStreamOutput output = new BytesStreamOutput();
+            output.setVersion(Version.V_5_0_0);
+            readRequest.writeTo(output);
+            assertEquals(output.bytes().toBytesRef(), requestBytes.toBytesRef());
+        }
+    }
 }

docs/build.gradle

@@ -368,3 +368,18 @@ buildRestTests.setups['range_index'] = '''
       body: |
         {"index":{"_id": 1}}
         {"expected_attendees": {"gte": 10, "lte": 20}, "time_frame": {"gte": "2015-10-31 12:00:00", "lte": "2015-11-01"}}'''
+
+// Used by index boost doc
+buildRestTests.setups['index_boost'] = '''
+  - do:
+      indices.create:
+          index:  index1
+  - do:
+      indices.create:
+          index:  index2
+
+  - do:
+      indices.put_alias:
+        index: index1
+        name: alias1
+'''

docs/reference/search/request/index-boost.asciidoc

@@ -6,6 +6,7 @@ across more than one indices. This is very handy when hits coming from
 one index matter more than hits coming from another index (think social
 graph where each user has an index).
 
+deprecated[5.2.0, This format is deprecated. Please use array format instead.]
 [source,js]
 --------------------------------------------------
 GET /_search
@@ -17,3 +18,23 @@ GET /_search
 }
 --------------------------------------------------
 // CONSOLE
+// TEST[setup:index_boost warning:Object format in indices_boost is deprecated, please use array format instead]
+
+You can also specify it as an array to control the order of boosts.
+
+[source,js]
+--------------------------------------------------
+GET /_search
+{
+    "indices_boost" : [
+        { "alias1" : 1.4 },
+        { "index*" : 1.3 }
+    ]
+}
+--------------------------------------------------
+// CONSOLE
+// TEST[continued]
+
+This is important when you use aliases or wildcard expression.
+If multiple matches are found, the first match will be used.
+For example, if an index is included in both `alias1` and `index*`, boost value of `1.4` is applied.

rest-api-spec/src/main/resources/rest-api-spec/test/search/40_indices_boost.yaml

@@ -0,0 +1,196 @@
+setup:
+  - do:
+      indices.create:
+          index:  test_1
+  - do:
+      indices.create:
+          index:  test_2
+
+  - do:
+      indices.put_alias:
+        index: test_1
+        name: alias_1
+
+  - do:
+      indices.put_alias:
+        index: test_2
+        name: alias_2
+
+  - do:
+      index:
+          index:  test_1
+          type:   test
+          id:     1
+          body:   { foo: bar }
+
+  - do:
+      index:
+          index:  test_2
+          type:   test
+          id:     1
+          body:   { foo: bar }
+
+  - do:
+      indices.refresh:
+        index: [test_1, test_2]
+
+---
+"Indices boost using object":
+  - skip:
+      version: " - 5.1.99"
+      reason: deprecation was added in 5.2.0
+      features: "warnings"
+
+  - do:
+      warnings:
+        - 'Object format in indices_boost is deprecated, please use array format instead'
+      search:
+        index: _all
+        body:
+          indices_boost: {test_1: 2.0, test_2: 1.0}
+
+  - match: { hits.total: 2 }
+  - match: { hits.hits.0._index: test_1 }
+  - match: { hits.hits.1._index: test_2 }
+
+  - do:
+      warnings:
+        - 'Object format in indices_boost is deprecated, please use array format instead'
+      search:
+        index: _all
+        body:
+          indices_boost: {test_1: 1.0, test_2: 2.0}
+
+  - match: { hits.total: 2 }
+  - match: { hits.hits.0._index: test_2 }
+  - match: { hits.hits.1._index: test_1 }
+
+---
+"Indices boost using array":
+  - skip:
+      version: " - 5.1.99"
+      reason: array format was added in 5.2.0
+
+  - do:
+      search:
+        index: _all
+        body:
+          indices_boost: [{test_1: 2.0}, {test_2: 1.0}]
+
+  - match: { hits.total: 2 }
+  - match: { hits.hits.0._index: test_1 }
+  - match: { hits.hits.1._index: test_2 }
+
+  - do:
+      search:
+        index: _all
+        body:
+          indices_boost: [{test_1: 1.0}, {test_2: 2.0}]
+
+  - match: { hits.total: 2 }
+  - match: { hits.hits.0._index: test_2 }
+  - match: { hits.hits.1._index: test_1 }
+
+---
+"Indices boost using array with alias":
+  - skip:
+      version: " - 5.1.99"
+      reason: array format was added in 5.2.0
+
+  - do:
+      search:
+        index: _all
+        body:
+          indices_boost: [{alias_1: 2.0}]
+
+  - match: { hits.total: 2}
+  - match: { hits.hits.0._index: test_1 }
+  - match: { hits.hits.1._index: test_2 }
+
+  - do:
+      search:
+        index: _all
+        body:
+          indices_boost: [{alias_2: 2.0}]
+
+  - match: { hits.total: 2}
+  - match: { hits.hits.0._index: test_2 }
+  - match: { hits.hits.1._index: test_1 }
+
+---
+"Indices boost using array with wildcard":
+  - skip:
+      version: " - 5.1.99"
+      reason: array format was added in 5.2.0
+
+  - do:
+      search:
+        index: _all
+        body:
+          indices_boost: [{"*_1": 2.0}]
+
+  - match: { hits.total: 2}
+  - match: { hits.hits.0._index: test_1 }
+  - match: { hits.hits.1._index: test_2 }
+
+  - do:
+      search:
+        index: _all
+        body:
+          indices_boost: [{"*_2": 2.0}]
+
+  - match: { hits.total: 2}
+  - match: { hits.hits.0._index: test_2 }
+  - match: { hits.hits.1._index: test_1 }
+
+---
+"Indices boost using array multiple match":
+  - skip:
+      version: " - 5.1.99"
+      reason: array format was added in 5.2.0
+
+  - do:
+      search:
+        index: _all
+        body:
+          # First match (3.0) is used for test_1
+          indices_boost: [{"*_1": 3.0}, {alias_1: 1.0}, {test_2: 2.0}]
+
+  - match: { hits.total: 2}
+  - match: { hits.hits.0._index: test_1 }
+  - match: { hits.hits.1._index: test_2 }
+
+  - do:
+      search:
+        index: _all
+        body:
+          # First match (1.0) is used for test_1
+          indices_boost: [{"*_1": 1.0}, {test_2: 2.0}, {alias_1: 3.0}]
+
+  - match: { hits.total: 2}
+  - match: { hits.hits.0._index: test_2 }
+  - match: { hits.hits.1._index: test_1 }
+
+---
+"Indices boost for nonexistent index/alias":
+  - skip:
+      version: " - 5.1.99"
+      reason: array format was added in 5.2.0
+
+  - do:
+      catch: /no such index/
+      search:
+        index: _all
+        body:
+          indices_boost: [{nonexistent: 2.0}, {test_1: 1.0}, {test_2: 2.0}]
+
+  - do:
+      search:
+        index: _all
+        ignore_unavailable: true
+        body:
+          indices_boost: [{nonexistent: 2.0}, {test_1: 1.0}, {test_2: 2.0}]
+
+  - match: { hits.total: 2}
+  - match: { hits.hits.0._index: test_2 }
+  - match: { hits.hits.1._index: test_1 }

test/framework/src/main/java/org/elasticsearch/test/TestSearchContext.java

@@ -156,11 +156,6 @@ public class TestSearchContext extends SearchContext {
         return 0;
     }
 
-    @Override
-    public SearchContext queryBoost(float queryBoost) {
-        return null;
-    }
-
     @Override
     public long getOriginNanoTime() {
         return originNanoTime;